Elastomers, such as, for example, seals and O-rings have long been known for their inherent resiliency. This resiliency permits these structural members to be used to effectively seal an opening between adjacent parts since these elastomers can be compressed within the space to form a sealing barrier. Thus, in the case of sealing a shaft, for example, with respect to a relatively rotatable surrounding housing, it has been common practice to provide an O-ring in the space between the shaft and the housing to effectuate an efficient seal in this area. Similarly, flat or disc types of washers normally used in valve members, utilize the inherent resiliency of the washer to effectuate the sealing action.
Another important characteristic of elastomers is the tendency of elastomeric seals to exhibit high values of sliding friction when installed under compression. One such use of an elastomer is in an oil well stuffing box. The stuffing box in used on pumping oil wells in conjunction with a through passing polished rod to effect pumping while maintaining a sliding seal to protect the environment from both liquid and gas emissions from the well production steam in the tubing below ground. Elastomers used in oil well stuffing boxes have not been totally successful in their intended function, and their failure has contributed to a major source of environmental pollution. The friction inherent in the elastomers themselves leads to flexural stresses and eventually to the elastomer breakdown, as it seems that there is a practical limit to the applied compression at installation beyond which the frictional drag of the rubber on the polished rod will result in heating sufficient to actually burn the seals and damage the polished rod. It is even possible to support the entire sucker rod string dead weight by tightening the seals. Thus, a seal installed with sufficient compression to actually effect the intended seal will fail due to friction whereas a relaxation of compression to allow operation will leak effluent to the environment.
While many elastomers may operate satisfactory under normal conditions, it has been found that the efficiency and life thereof are unfavorably affected when these elastomers are subjected to certain adverse types of conditions that frequently occur in industrial use. Thus, for example, where the rubber sealing member is subjected to a high temperature, the major constituents of the seal may decompose to a fluid state or chemically break down to release volatile substances, thereby rendering the sealing unit useless. Most elastomers are by nature, liquids, with a normal tendency to return to the liquid state. The elastomers are restrained from returning to this liquid state by cross linking bonds between the polymeric chains. In actual use, as a result of stress, chemical and thermal effects, the cross linking bonds degenerate and, in the breakdown process, will offer reactive carbon atoms to the surroundings. This carbon reacting with metals in a seal bore forms metal carbide residue on the contacting metal.
Additional problems associated with the use of elastomers as sealing structure result if the sealing member is subjected to a corrosive action, wherein the body portion will be eroded or corroded to a point where the member will not be able to effectuate a satisfactory seal. Other extreme conditions that result in premature deterioration of the sealing member or inefficiency thereof, include pressure extremes and subjection to certain compounds and gases that operate to decompose or dissolve the body portion of the elastomer. Similarly, when exposed to low temperatures the inherent resiliency of an elastomer is lost due to embrittlement occurring, with actual fracture frequently occurring.
Various methods have been proposed to protect elastomers and/or enhance their function by various wet chemistry metal plating methods. However, these methods have been unsuccessful due to the lack of adhesion of the metal/elastomer interface. Flexure, particularly in dynamic seals, will typically cause the elastomer to tear through the thin metal shells in a short period of time. Plating voids and/or stress cracks permit the elements of the working environment to enter the pure elastomer and a normal failure progression will occur. The very presence of shattered film particles can lead to the formation of a leak site.
Therefore, to be effective and of lasting value, an applied metal film must intimately conform to the surface topography of the elastomer. The applied metal film must also react in response to flexure and/or compression of the elastomer. To achieve these results, the film must be atomically bonded at the molecular level, and the value of adhesive strength must be in excess of 2,000 psi. Normal wet chemistry plating methods have failed to achieve this result.
A need has thus arisen for an elastomer and method for stabilization and lubrication which will result in a stable as well as lubricated elastomer that will ensure that the lubricant is not displaced by adhesion failure when the stresses inherent in the elastomer's operation are experienced.